Best way to take multiple screenshots?

I'm re-watching an anime and I suddenly feel like taking screenshots of my favorite scenes on every episode, but I don't want to keep pausing the video to take them,
I wanna know if there's a way to just take a screenshot and it immediately saves itself somewhere, like you do on the itouch and iphone.
I've been thinking there must be a way since some people actually take over 300 screenshots of anime, and I doubt they copy and paste every single one

FRAPS has a screen-capture feature. It's what most people use.